[material-ui][Alert] Add slots and slotProps type to theme

packages/mui-material/src/Alert/Alert.d.ts

@@ -33,7 +33,7 @@ export type AlertSlotsAndSlotProps = CreateSlotsAndSlotProps<
   }
 >;
 
-export interface AlertProps extends StandardProps<PaperProps, 'variant'> {
+export interface AlertProps extends StandardProps<PaperProps, 'variant'>, AlertSlotsAndSlotProps {
   /**
    * The action to display. It renders after the message, at the end of the alert.
    */
@@ -133,4 +133,4 @@ export interface AlertOwnerState extends AlertProps {}
  * - [Alert API](https://mui.com/material-ui/api/alert/)
  * - inherits [Paper API](https://mui.com/material-ui/api/paper/)
  */
-export default function Alert(props: AlertProps & AlertSlotsAndSlotProps): JSX.Element;
+export default function Alert(props: AlertProps): JSX.Element;

packages/mui-material/src/Alert/Alert.spec.tsx

@@ -0,0 +1,14 @@
+import { CloseRounded } from '@mui/icons-material';
+import { createTheme } from '@mui/material';
+
+createTheme({
+  components: {
+    MuiAlert: {
+      defaultProps: {
+        slots: {
+          closeIcon: CloseRounded,
+        },
+      },
+    },
+  },
+});